Warning: Cam control is an advanced feature. This should only be set-up and operated by experienced tuners. Failure to correctly set up cam control can result in the cam timing operating unpredictably and possibly result in engine damage. DO NOT adjust anything you are not completely sure of !
At all times, the VVT runtime values can be viewed on the VVT tab of the Runtime Values window (F12 key).
Before commencing VVT tuning all cam and crank sensors must be wired correctly (including correct polarity). The Trigger Offset also needs to have been set correctly with a timing light.
Tuning VVT Control can be done by either choosing a pre-set configuration or using a custom setup. Default configurations hide the complexities of the tuning values and are strongly recommended. The following options are provided for configuration of default and custom setups:
This setting contains a list of pre-set VVT configurations and a User Defined option which allows the user to setup a completely custom configuration.
If your engine type is not listed as a pre-set configuration you can contact your Link dealer to find out if another pre-set configuration will work or use the User Defined VVT mode.
This setting is only visible when in User Defined mode and is used to set the number of banks the engine has (1 or 2). When set to 1 bank PCLink will hide the settings for Bank 2.
Variable Cams Bank 1 & Variable Cams Bank 2
These settings are only visible when using User Defined Mode and Variable Cams Bank 2 is only visible when Number of Banks is set to 2. These settings are used to set which cams are VVT controllable on each bank and hide the VVT settings for the cams that are not controllable, options are Inlet, Exhaust or Inlet & Exhaust.
This setting provides a method for the user to see the angle of each tooth on a specific cam and an automatic calibration option which will fill out the Tooth Count and Tooth Offsets settings for all cams.
The Calibrate option when selected performs a calibration of each cam where it calculates the Tooth Count and Tooth Offsets for each cam and fills in these settings.
The Tooth Count and Tooth Offsets values can be filled out manually using the information from the Cam Angle Test for each cam but it is recommended to just use the calibrate function.
The purpose of the individual cam options is to display the position of each tooth on the cam in crankshaft degrees ATDC so the user can debug any issues that might be occuring. Cam angle test information can be found in the VVT tab of the F12 runtime data menu.
To activate the Cam Angle Test Function, perform the following steps:
1.Ensure a Cam Position Digital Input has been wired and configured.
2.Select the appropriate VVT Control Channel in the Cam Angle Test list.
3.Observe the cam teeth positions by looking at the parameter Cam Angle #X on the VVT tab of the Runtime Values window (F12 Key). The number of teeth is visible as
4.Run the engine above the VVT RPM Lockout and ECT Lockout values.
5.The position at which each cam pulse occurs will be displayed.
This setting allows the user to use the default PID values or to use their own custom PID values. This setting is custom by default and hidden when using User Defined Mode.
When PID Setup is set to Custom, the following items cam be adjusted for each VVT channel:
This value determines the engine speed (RPM) that must be exceeded before the VVT control system will become active, this allows VVT control to be disabled at lower engine speeds. At lower engine speed oil pressure is low and reluctor position signals can have insufficient amplitude which can affect the accuracy of the VVT control system. When the lockout condition has not been met the cams will be uncontrolled and will sit in their relaxed position. Typical values range from 500 RPM (on at idle) to 1500 RPM (off at idle). This lockout does have hysteresis applied to it to prevent rapid switching on and off when hovering around the lockout value.
This value determines the engine coolant temperature that must be exceeded before the VVT control system will become active, this allows VVT control to be disabled at lower engine temperatures when the oil is too cold. When the lockout condition has not been met the cams will be uncontrolled and will sit in their relaxed position. Typical values range from 20 to 50 degrees Celsius.
Active Inlet Tables & Active Exhaust Tables
This setting allows the user to have multiple different Inlet or Exhaust Target Tables and to switch between them at will.
Inlet Table 2 (or 3) Activation & Exhaust Table 2 (or 3) Activation
These settings are used to select which input will be used to switch to the VVT Inlet or Exhaust Target Table of the same number.
When turned on the Duty Cycle of the Auxiliary is adjusted based on how far the battery voltage is from 14V (while still being clamped between the min and max). This means that the actual position of the cam should be more consistent with the desired position over variations in the vehicle voltage.
Inlet Fully Retard Position & Exhaust Fully Advance Position
Normally Link VVT Target Tables are referenced to the variable valve timings natural or relaxed position. For inlet cams, a VVT Inlet Target Table number of 0.0 will mean the cam is in its most retarded position, 30 would mean it is advanced by 30 degrees. Some tuners find it easier to relate to actual engine position degrees rather than just degrees of advance, these settings allow the numbers in the VVT Target Tables to show the actual cam lobe position relative to the engine position by acting as an offset to the relaxed positions. VVT tuning can then be performed by setting the desired cam lobe position relative to the engine position for various operating conditions.
Note: This function requires that the exact position of the cam lobes is known, this must be found by measurement rather than using paper specifications.
·To setup the Fully Retard Position for the inlet Cam simply enter the crankshaft position of the inlet lobe centre at its fully retarded position into the Inlet Fully Rtd Position setting, e.g 108 degrees ATDC. The numbers in the VVT Inlet Target Table will now be the position of the lobe centre After Top Dead Centre (ATDC).
·To setup the Fully Advance Position for the exhaust Cam simply enter the crankshaft position of the exhaust lobe centre at its fully advanced position into the Exhaust Fully Adv Position setting, e.g 109 degrees BTDC. The numbers in the VVT Exhaust Target Table will now be the position of the lobe centre Before Top Dead Centre (BTDC).
Inlet/Exhaust Advance/Retard Tooth Tolerance
These settings are only visible when using the User Defined Cam Mode.
The Retard and Advance Tooth Tolerance settings for the Inlet and Exhaust Cams sets the maximum movement range of the cam that the Cam Sensor will allow a tooth to be detected in. If no tooth is detected in the set range an error will be dispalyed on that cam's Signal Status.
Cold Temperature Gain Compensation
This setting allows the user to increase the gains when the engine is cold to compensate for the colder oil. It is added as a percentage of the proportional gain multiplied by the number of degrees C below 80deg C.
For example a gain of 1%/deg C and an ECT of 40 degrees C The Proportional Gain values will be increased by 1% x (80 - 40) = 40%.
This setting allows the user to choose between the standard single VVT solenoid output that is used on most vehicles or the Dual Solenoid output style typically used in BMW engines that have VANOS.
If using a Dual Solenoid output you will need -ve values in the Min DC Clamp tables.
VVT Inlet & Exhaust Target (Tables)
Tables are allocated for VVT control camshaft position tuning, up to 3 target tables can be allocated for the inlet and exhaust (3 inlet and 3 exhaust).
The VVT Inlet & Exhaust Target Tables define the target cam position in degrees advanced. A number of 0 in this table will mean that the cam will be at its relaxed position (assuming the Inlet Fully Rtd and Exh Fully Adv Position settings are 0). A positive number indicates advance and a negative number indicates retard. Note that the most retarded position for the inlet cam is its least aggressive position and the most advanced position for the exhaust cam is typically its least aggressive position so the inlet target table will typically use positive values and the exhaust target table will typically use negative values. Also note that if Inlet Fully Rtd and Exh Fully Adv Positions are non zero the numbers in the VVT Inlet Target Table will need to be shifted by these values.
Each Cam:
These settings are available for each cam but only the settings for the cams in use will be visible. Specific vehicle VVT Modes have the number of banks and adjustable cams hardcoded meaning cams that are not variable from factory will be hidden.
This setting selects the input for this cams trigger signal. In order to vary cam advance/retard, the current position must be known, Link ECUs use Digital Inputs and Trigger 2 to measure cam position. Input can be from a reluctor, hall effect or optical sensor but reluctor Inputs might not work as well at low speed when connected to a DI input.
Only Digital Inputs 1 to 4 and Trigger 2 can be used as Cam Position Digital Inputs. Although Digital Inputs can be wired to any cam position sensor, the following convention should be used to conform with other Link wiring diagrams and base configurations:
·Bank 1 Inlet - Trigger 2 (or Digital Input 1 if the engine has separate sync and cam angle sensors)
·Bank 2 Inlet - Digital Input 2
·Bank 1 Exhaust - Digital Input 3
·Bank 2 Exhaust - Digital Input 4
When using digital input for the cam trigger signal its pull-up and active edge need to be set (Typically pull-up ON for Hall and OFF for Reluctor/VR). The Active Edge setting determines which edge of the cam position sensor signal will be used to determine VVT cam position, for reluctor sensors always select a Falling active edge and for hall sensors this edge could be rising or falling. Selection of the wrong edge will affect setting the Offset value.
This setting selects the Auxiliary Output that will be used to control the cam's position.
In order to vary cam advance/retard, the VVT control solenoid must be driven by the ECU. All VVT Control Auxiliary Outputs drive the solenoids to ground. The other side of the solenoid must be wired to an ignition switched supply (NOT hot fed).
Although Auxiliary Outputs can be wired to any VVT solenoid, the following convention should be used to conform with other Link wiring diagrams and base configurations:
·Bank 1 Inlet - Auxiliary Output 1
·Bank 2 Inlet - Auxiliary Output 2
·Bank 1 Exhaust - Auxiliary Output 3
·Bank 2 Exhaust - Auxiliary Output 4
This setting is only visible when the Valve Type is set to Dual Solenoid.
The Auxiliary selected here works in conjunction with the PWM Output Auxiliary to control VVT setups that require separate solenoids for advancing and retarding the each cam. A typical example of these systems is BMW VANOS.
Use this setting to select the output that has been wired to the solenoid that returns the cam to it's base position. This output becomes active when the desired duty cycle drops below 0 and so the Minimum DC Clamp values must be negative for this output to work.
This setting controls the frequency of the PWM used to control this cam's solenoid, typical values would be between 250 and 300Hz.
This setting is only visible when only visible when PID Setup is set to Custom.
This setting allows the cam to use the Base Duty Cycle Proportional Gain, Integral Gain and Derivative Gain values from one of the other cams. This means the user will only need to change the values in one or two areas (depending on the setup) rather than having to change the values on each cam individually.
Example:
A Subaru engine has two inlet cams and two exhaust cams. On some models, all of these have variable timing. To simplify tuning the VVT control, it would be better to pair up the VVT PID tuning Settings for the Bank 1 and Bank 2 inlet cams and pair up the VVT PID Tuning Settings for the Bank 1 and Bank 2 exhaust cams. All four cams will be controlled independently but both inlet cams will use the same PID Tuning Settings and both exhaust cams will use the same PID Tuning Settings. Set the Control Algorithms for each cam as follows:
·Set Bank 1 Inlet Control Algorithm to Inlet Bank 1
·Set Bank 2 Inlet Control Algorithm to Inlet Bank 1
·Set Bank 1 Exhaust Control Algorithm to Exhaust Bank 1
·Set Bank 2 Exhaust Control Algorithm to Exhaust Bank 1
The VVT PID Tuning Settings for both Bank 2 cams will now have no effect and not be visible. Both Inlet cams VVT PID Tuning Settings will now be adjusted using the Bank 1 Inlet VVT Control settings. Both Exhaust cams VVT PID Tuning Settings will now be adjusted using the Bank 1 exhaust VVT control settings.
This setting sets the number of teeth on the cam trigger that the ecu will look for, this value is filled out automatically when the Cam Angle Test Calibrate function is run.
This setting is only visible when only visible when this cams Control Algorithm is set to this cam, PID Setup is set to Custom and Valve Type is set to Single Solenoid.
This setting controls the base Duty Cycle, the value before any gains are added or subtracted.
This setting is only visible when only visible when this cams Control Algorithm is set to this cam and PID Setup is set to Custom.
This setting adjusts the Proportional Gain of the VVT Control's PID algorithm, increasing this number increases the proportional gain, decreasing this number decreases the proportional gain.
This setting is only visible when only visible when this cams Control Algorithm is set to this cam and PID Setup is set to Custom.
This setting adjusts the Integral Gain of the VVT Control's PID algorithm, increasing this number increases the integral gain, decreasing this number decreases the integral gain.
This setting is only visible when only visible when this cams Control Algorithm is set to this cam and PID Setup is set to Custom.
This setting adjusts the Derivative Gain of the VVT Control's PID algorithm, increasing this number increases the derivative gain, decreasing this number decreases the derivative gain.
This setting adjusts the ability of the VVT Control to reject inconsistencies in the cam position signal input, inconsistencies occur due to factors such as cam belt slack and engine speed variation. Increasing the filter number allows smoother control of cam positioning, but will decrease the response time of the VVT Control. It is recommended to use a setting between 4 and 6. Note that increasing the Filter value adds delay to the control loop which may cause instability.
Inlet/Exhaust Bank 1/2 Tooth Offsets Table
This table allows the user to manually enter the absolute angle (relative to cylinder 1 tdc) of each of the cam's trigger teeth, these values are filled out automatically when the Cam Angle Test Calibrate function is run.
Inlet/Exhaust Bank 1/2 Min & Max DC Clamp Table
This setting is only visible when only visible when this cams Control Algorithm is set to this cam and PID Setup is set to Custom.
This setting controls the maximum duty cycle that will ever be applied to the cam control solenoid based on engine coolant temperature. Limiting the range of the VVT control solenoids duty cycle helps improve VVT Control stability. As engine coolant temperature changes, due to changes in oil viscosity and component clearances, different duty cycle ranges are required for VVT control operation. At any given temperature, the VVT solenoid will operate at duty cycles between the values given in the Max and Min DC Clamp tables.